Thursday, September 23, 2010

I ordered Christopher Ryan and Cacilda Jethá’s Sex at Dawn from Amazon shortly after Dan Savage pimped it on his weekly podcast. I was intrigued by the idea of an evolutionary account of human sexuality that differs from the typical account offered by evolutionary psychology. Sadly, I was underwhelmed. Here’s what I wrote in the comments of a Dan Savage blog post on the subject about three weeks ago:

Dan, I love you, your column, and your podcast. But I'm reading Sex at Dawn -- because you suggested it -- and speaking as an academic, I'm not impressed. I'm having a hard time even finishing it, because on every single page there's an unsupported assertion, straw-man argument, or cherry-picked example that makes me want to throw it at the wall.

If you're looking for scientific support for your anti-monogamy position, you can find it in the *traditional* account in evolutionary psychology -- the one that Sex at Dawn tries so hard to debunk. The traditional account does not say that monogamy is easy. On the contrary, the traditional account says that cheating (in the sense of straying from monogamous relationships) is to be expected for evolutionary reasons. It is, as you say so often on your show, perfectly natural for people to want to have sex with people other than their primary partner.

Of course, it's also perfectly natural for people to get jealous. There are good evolutionary reasons for that, as well. It may seem hypocritical to be a jealous cheater, but natural selection does not breed for consistency -- it breeds for reproductive advantage. When the authors of "Sex at Dawn" say their story is more parsimonious, what they mean is that it paints a simple picture of human psychology that requires no hypocrisy. But we are hypocritical, so their explanation doesn't fit with the messy psychological reality. And that's an insight that will actually help your advice-giving career. People make a lot more sense when you understand their built-in contradictions.

When you're giving people advice on sex and relationships, you have a very critical eye. You should cast that same critical eye on the books you're pimping.

I’ve finished the book now, and my opinion hasn’t changed.What most disappointed me was the authors’ deliberate conflation of Victorian values with modern evolutionary psychology, as though they were exactly the same position. By so doing, they make it sound as though any refutation of the former were also a refutation of the latter. They spend precious little time exploring the very significant differences between the faith-based position of the Victorians and the science-based position of the evolutionary psychologists. Every time they cite Victorian-types taking an absurd position on the subject of sex, they invite us to conclude that evolutionary psychologists share in the absurdity. By the end, they come close to saying evol psych is responsible for male and female genital mutilation.

The authors also spend a great deal of time glorifying the lives of primitive peoples, leading us to believe our distant ancestors led long happy lives filled with nutritious food and plenty of sex. Yet they also try to distance themselves from the “noble savage” position, saying (for instance) that “[t]hese pre-agricultural societies were no nobler than you are when you pay your taxes or insurance premiums” (p. 9). But that’s just a dodge. Ultimately, they really do glorify primitive living conditions. Consider, for instance, their approving quote from Kurt Vonnegut (p. 149): “Human beings will be happier – not when they cure cancer or get to Mars or eliminate racial prejudice or flush Lake Erie but when they find ways to inhabit primitive communities again. That’s my utopia.” Ryan and Jethá apparently agree.

Their overarching argument has numerous weak spots, but the weakest is their analysis of jealousy. Jealousy matters because it’s a key point on which their “promiscuous primitives” hypothesis differs from the standard account, which says that (a) males will be jealous of other males because they reduce paternity certainty, and (b) females will be jealous of other females because they threaten their children’s share of male-provided resources. But if primitive people really did mate in a polyamorous fashion in a context of abundant resources, as the authors of Sex at Dawn claim, then they need a compelling story on the origin of jealousy. Yet their argument boils down to the claim that jealousy can be controlled with appropriate social norms. Which is true; so can most human emotions. But that does nothing to explain why jealousy is there in the first place, nor why such strong social norms are needed to keep it in check.

The authors refute the claim that women have lower sex drive than men by noting, more than once, that strong social norms have been instituted to keep it down. “Why the electrified high-security razor-wire fence to contain a kitty-cat?” they ask (p. 39). On this point, I think they have a reasonable claim, and female libido may indeed be naturally higher than is typically recognized. But the same line of argument can be directed at their own position on jealousy. If jealousy is not a natural impulse, then why are such strong social norms required to control it?

The overarching flaw in Ryan and Jethá’s approach is the either/or mentality they apply to a wide range of questions. Humans are either more like chimps, or more like bonobos. (Why can’t we have characteristics of both, as well as some characteristics unique to us?) We are either naturally warlike or naturally peaceful. (Why not a tendency to keep the peace locally while making war with strangers?) We evolved in a context of either abundance or constant scarcity. (Why not stretches of both?) We are either relentlessly selfish or fully altruistic. (Why not guardedly altruistic with a tendency to exploit opportunities for selfish gain?) We are either faithfully monogamous or highly promiscuous. (Why not generally monogamous with opportunistic exceptions?) On all of these questions, Ryan and Jethá take the latter position – and then support it by showing exceptions to the former. Ultimately, the whole book reads like an extended lesson in how to commit the fallacy of the excluded middle.

3 comments:

I'm sorry you were underwhelmed, but I can't help thinking you somehow missed a lot of what you claim isn't there.

Your main complaint, as expressed in your summation, is that we take an overly simplistic either/or approach to human evolution.

You write: "The overarching flaw in Ryan and Jethá’s approach is the either/or mentality they apply to a wide range of questions ... Ultimately, the whole book reads like an extended lesson in how to commit the fallacy of the excluded middle."

It's hard to see how you could have read the book and still make this case. We repeatedly attempt to convey the idea that this either/or approach is misguided and ill-applied to creatures as complex as human beings. I'm not sure how you missed passages like this one, on page 198, where we explicitly address your point:

"Asking whether our species is naturally peaceful or warlike, generous or possessive, free-loving or jealous, is like asking whether H2O is naturally a solid, liquid, or gas. The only meaningful answer to such a question is: It depends."

It's possible my review was slightly unfair on that specific point. But upon re-reading the chapter you cite (which focuses on whether humans are naturally peaceful or warlike), I come away with the same impression. You do say "it depends" -- but depends on what? Apparently, on whether humans are pre-agricultural or post-agricultural. In your description of pre-agricultural human societies, you give the impression that they rarely if ever went to war. As you say in the passage immediately following the one you quote, "Under conditions typical of ancestral environments, human beings would have had much more to lose than to gain from warring against one another."

In other words, with respect to humans in the environment in which we evolved, I think you do indeed take something close to a polar position. Humans in that environment, you claim, would rarely if ever have gone to war.

In any case, the war/peace dichotomy is just one of many where I think you've excluded the middle. This is nowhere more evident than in your central thesis: that humans are naturally polyamorous. In supporting this position, you repeatedly draw attention to the number of men and women in modern societies who cheat on their primary partners. But the traditional account of evolutionary psychology doesn't deny that fact at all; on the contrary, monogamy-with-cheating is one of the phenomena that evol psych sets out to explain. So evidence that people cheat cannot provide evidence that supports your story over theirs -- unless you have implicitly taken a dichotomous either/or position in which any deviation from strict monogamy constitutes support for its polar opposite.

As I recall, there are many other passages in the book where you recognize a more sophisticated position -- as, for instance, when you distance yourself from the "noble savage" position. But taking the book as a whole, the either/or thinking is pervasive.

Hi Glen. If you're married to that reading of the book, that's ok. I don't think it's an accurate reading, but what do I know? Every mother thinks her baby is beautiful, right?

You ask, "depends on what?" We answer that question in some detail. Depends on whether or not there are accumulated resources worth fighting over. Depends on population density. Depends on the availability of alternative food sources that don't require risking one's life. That's what the chapter was about—answering the question: depends on what?

Of course, you're correct that EP offers an explanation for why so many people cheat, despite the rather draconian punishments they face. And Ptolemy offered an explanation for why the stars seemed to move backwards in the sky sometimes. But like the pre-Copernican cosmology, the EP explanations are strained, self-contradictory and undermined by the facts.

No doubt, there is a lot of gray area in these issues, and I think you're wise to look for the middle ground in intellectual debates, but I think your criticism is misapplied in this case.

But as I said, I recognize that mine is anything but an objective perspective.